Publications scientifiques de l'Université de Reims Champagne-Ardenne
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ABIOMAR - Etude abiotique des mares de la réserve biologique dirigée de Verzy - Rapport final
No full textL’objectif de l’étude est de comprendre le comportement hydrodynamique des mares de la Réserve Biologique Dirigée (RBD) de Verzy dans la Montagne de Reims. Elle s’organise autour d’une analyse multi-sites et croisée ou pluridisciplinaire, avec des approches géomorphologiques, pédo-géochimiques, hydrologiques et hydrochimiques, sur une année voire, idéalement plusieurs années. Elle repose sur l’analyse des documents d’archives, une approche multicritère, un traitement des images LiDAR, des mesures de terrain, des prélèvements et des analyses en laboratoire, pour proposer une modélisation conceptuelle et hydrodynamique des mares. Ce projet permet de lancer une dynamique de recherches pluriannuelles pour améliorer le plan de gestion de la RBD. Après avoir inscrit les mares dans leur contexte géomorphologique, pédologique et avoir caractérisé leur comportement hydrodynamique, les recherches peuvent s’orienter vers la biocénose
Design and Optimization of Auxiliary Control in Active Fault Detection for Aircraft Systems
No full textInternational audienceActive fault detection excites a dynamic system by an auxiliary control input such that undetectable faults are revealed. For aircraft systems, it has been pointed out by some relevant works that certain actuator faults cannot be effectively detected in time without actively exciting the aircraft dynamics. However, existing works using auxiliary control for aircraft fault diagnosis mostly consider rather simple signals, which cannot guarantee the fault detection without degrading the performance of nominal flight operation. Since optimal auxiliary control input design for aircraft systems has not been extensively studied yet, we are motivated to formulate the design problem and propose an optimization scheme in this paper. Specifically, the proposed auxiliary control design problem addresses the active fault detection to multiple potential faults simultaneously under unknown-but-constrained inputs and nonlinear flight dynamics, and minimization of the intervention to nominal flight performance is considered. The auxiliary control design problem can be solved by the proposed bi-level optimization scheme without conservative relaxations, and an effective strategy for finding initial guesses is proposed. Numerical results and tests are presented to demonstrate the effectiveness of the proposed formulation and the optimization scheme for auxiliary control design
Pas de DGS pour une communauté de communes, et alors ?
No full textInternational audienceNote sous TA Nancy, 3 juin 2025, no 240163
Comparaisons et connexions en didactique de la littérature , Louichon Brigitte (dir.), Bordeaux : PU de Bordeaux (2025)
No full textInternational audienc
Seasonal variations of Titan’s haze and mist layers monitored by VIMS-IR onboard Cassini
No full textInternational audienceThe Cassini orbiter around Saturn monitored Titan with multiple instruments 13 years, between 2004 to 2017. This is about half of a Titan year and this period included a major seasonal change at the North Spring Equinox (NSE) in 2009 that could be observed. The Visual and Infrared Mapping Spectrometer (VIMS) onboard Cassini produced a large amount of observations of Titan generally presented under the form of spectro-images. The observations with the IR part of VIMS detector are taken in a spectral range between 0.88 to 5.12μm and with a resolving power between R= λ/Δλ = 120 and 180. The spatial resolution of the images depends on the observation and is few hundreds of meters at the best. In this study, we retrieved the distribution of the photochemical haze (above 80 km) and the condensate mist layer (below 80 km) as a function of latitude, altitude, and tile throughout the Cassini era. We found a haze latitudinal distribution with an extinction increasing from the south to the north at the beginning of the Cassini mission. The distribution evolved around the North Spring Equinox and a turnover was completely achieved at the end of the Cassini mission. This evolution is linked to the stratospheric circulation that blows from the summer hemisphere to the winter polar region. The latitudinal distribution of the mist layer evolves differently than the haze distribution because it depends on both the circulation pattern in the low atmosphere and on the conditions of condensation for several species. The distribution of the mist layer is also modulated with the seasons, but always increases from the equator and inter-tropical latitude band to the poles
Complementary NMR analyses of cellulose-based assembly reveal how multi-scale structure governs saccharification efficiency in steam-exploded wood
No full textInternational audienceLignocellulosic biomass is a promising alternative to fossil resources to produce biobased products. However, thisbiomass is highly recalcitrant to enzymatic processes and requires a pretreatment step to overcome it. To understandthe role of lignocellulose polymers organization on recalcitrance, characterization at different scales iscritical, preferentially by employing non-degradative techniques which maintain sample physical integrity. Thisrequires to combine several techniques thus limiting their application. In this study, structural and morphologicalmodifications caused by steam explosion pretreatment on oak, poplar and spruce wood were enlightened using acombination of advanced 13C solid-state NMR and time-domain NMR techniques. Over increasing pretreatmentseverity, hemicelluloses content was decreased and amorphous cellulose was partially depolymerized, leading tohigher cellulose crystallinity: a swelling of the overall polymer matrix was thus observed. A relatively constantwater mobility associated to a reduction in pore size were observed, revealing that only a specific pore range of5–15 nm generated at middle severity pretreatment is favorable to enzyme diffusion and hydrolysis reaction.Interestingly, β-O-4 bonds content and enzymatic hydrolysis yields were highly correlated, confirming thepeculiar role of lignin in recalcitrance. Overall, this work demonstrates that structural information based on NMRapproaches can reveal biomass species-dependent features explaining the variable saccharification efficiencyover steam explosion pretreatment severity
Experts’ recommendations for the management of adult patients with cardiogenic shock
No full textInternational audienceThe last specific international European recommendations regarding the management of cardiogenic shock (CS) regardless of the etiology were issued over 10years ago. We present herein recommendations for the management of CS in adults, developed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system by an expert group of from the French Intensive Care Society [Société de réanimation de langue française (SRLF)] and the French Society of Cardiology [Société française de cardiologie (SFC)], with the participation of the French Society of Anesthesia and Intensive Care [Société française d'anesthésie et de réanimation (SFAR)], and the French Society of Thoracic and Cardiovascular Surgery [Société française de chirurgie thoracique et cardio-vasculaire (SFCTCV)]. The recommendations covered six fields of application: CS teams and expert centers, symptomatic medical management, etiological management, organ support, temporary circulatory support and de-escalation and early post-CS management. Twenty-three \"Patient Intervention Comparator Outcome\" (PICO) questions were identified, leading to 41 recommendations regarding management of CS in adult patients. Seven recommendations were scored with high level of evidence (Grade 1), 11 with moderate level of evidence (Grade 2) and 17 with low level of evidence (Expert opinion). In 6 cases, the experts were not able to give an answer. All of the recommendations obtained strong agreement from the expert committee. The experts highlight the fact that optimal management of CS requires organization including a structured, multidisciplinary shock team and regional referral network, applying standardized protocols for diagnosis and staging. Early etiological treatment-such as culprit-lesion revascularization or urgent valve intervention-is central to improve outcomes. Hemodynamic support should prioritize norepinephrine as first-line vasopressor and privilege selective inotrope use. Temporary mechanical circulatory support (Impella, VA-ECMO) should be reserved for carefully selected patients following discussion by the expert team
Artificial intelligence assisted Mortality Risk stratification in patients with Eisenmenger syndrome
No full textInternational audienceIntroductionMortality risk stratification is crucial for managing Eisenmenger syndrome, a severe form of congenital heart disease with pulmonary arterial hypertension. Some mortality determinants have been identified but a risk score remains to be validated.ObjectiveThis study aimed to develop and validate the AI-MUSES risk score, an artificial intelligence (AI)-assisted tool for mortality risk stratification in these patients.MethodThis study included 1,634 adult patients (> 16 years) with Eisenmenger syndrome from two independent multicentre international cohorts (development cohort: 1,098 patients; validation cohort: 536 patients). The primary outcome was all-cause mortality. Using traditional Cox regression models, the MUSES-1 and MUSES-2 scores incorporated variables such as age, oxygen saturation (SaO2), pericardial effusion, shunt type, cardiac rhythm, and 6-minute walk test (6MWT) distance.ResultsAn AI-driven model (AI-MUSES) was developed with variables selected using the Random Survival Forest tool, and the fractional polynomial method applied to refine and transform predictors. Four key predictors were retained: pre-tricuspid shunt, SaO2 <78%, presence of pericardial effusion and 6-minute walk test distance < 434 m. The AI-MUSES score demonstrated excellent discrimination, with a c-statistic of 0.756 in the development cohort and 0.762 in the validation cohort. Cross validation in the develoment cohort demonstrated excellent discrimination with a c-statistic of 0.741 (0.060) on test-train. Kaplan–Meier survival curves confirmed its ability to stratify patients into three distinct risk categories: low risk (requering follow up), intermediate risk (referral to transplantation centers) and high risk (transplantation) (Fig. 1).ConclusionThe AI-MUSES score provides a simple, reliable, and externally validated risk stratification tool for patients with Eisenmenger syndrome. By identifying patients at high risk of mortality, the score could facilitate timely referral for transplantation and enhances personalized management strategies